compiler: add support for import/export statements

This commit introduces syntax level support for ES6 style module import
and export statements. Imports are resolved at compile time and the
corresponding module code is compiled into the main program.

Also add testcases to cover import and export statement semantics.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/custom/04_modules/01_export_variable_declaration b/tests/custom/04_modules/01_export_variable_declaration
new file mode 100644
index 0000000..19a1c11
--- /dev/null
+++ b/tests/custom/04_modules/01_export_variable_declaration
@@ -0,0 +1,29 @@
+Variable declarations can be prepended with `export` to automatically
+export each variable using the same name as the variable itself.
+
+Updates to the variable after the export are reflected properly in
+the including scope.
+
+-- File test-var-decl.uc --
+export let a, b, c;
+export let d = 4, e = 5, f = 6;
+export const g = 7, h = 8, i = 9;
+
+a = 1;
+b = 2;
+c = 3;
+-- End --
+
+-- Testcase --
+import { a, b, c, d, e, f, g, h, i } from "./files/test-var-decl.uc";
+
+print([ a, b, c, d, e, f, g, h, i ], "\n");
+-- End --
+
+-- Args --
+-R
+-- End --
+
+-- Expect stdout --
+[ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
+-- End --